The present invention relates generally to metal/ceramic composite structures and methods of making same, and more specifically, to a tantalum-carbide ceramic nozzle throat made by diffusion bonding tantalum-carbide/tantalum2-carbide to tantalum. In particular, a nozzle throat is made by forging a ceramic layer to a tantalum metal ring at high temperatures and pressures.
Materials used for rocket nozzle throats, such as those used in tactical and strategic missiles, must survive severe thermal environments for anywhere from two seconds to over one minute. In previous long-range missiles, performance was the primary design driver. High performance goals led to the usage of expensive, exotic materials in the construction of the nozzle. One key component of the nozzle is the nozzle throat section, where the environment is most severe. Most long-range missiles in use today use carbon-carbon material. Carbon-carbon performs adequately but it is highly labor intensive, often taking up to two years to deliver one nozzle throat section, thus rendering the nozzle throat very expensive to produce. Less expensive materials have been fabricated into nozzle throats but failed to perform as well as carbon-carbon.
An object of the present invention is to provide a rocket nozzle throat that can be manufactured at substantial cost savings relative to carbon-carbon throats. This is achieved by the method of making rocket nozzle throats in which a ceramic material is net molded and bonded to a metallic liner, thereby reducing its manufacturing time compared to that of carbon-carbon.
Another object of the present invention is to provide a rocket nozzle throat that has better performance, in terms of erosion, than that of carbon-carbon, it being understood that lower erosion rates lead to improved missile range.
These and other objects of the invention are met by providing a rocket nozzle throat that includes a refractory metal ring and a ceramic layer net molded and diffusion bonded to the inner surface of the metal ring. Preferably, the ceramic is made of a mixture of tantalum carbide and tantalum2 carbide (TaC/Ta2C), here after referred to as tantalum carbide, and the metal ring is made from tantalum (Ta).
The refractory metal ring is further preferably made from a material selected from the group consisting of tantalum, tantalum alloys, molybdenum alloys, hafnium alloys, titanium alloys, tungsten alloys, and niobium alloys. Examples of suitable tantalum alloys include Ta-10W, Ta-2.5W, and Ta-40Nb. Another alloys that could be used is xe2x80x9cC103,xe2x80x9d which is 89% Nb, 10% Hf, and 1% Ti.
These and other objects of the invention will become more apparent from the following detailed description when taken in conjunction with the illustrative embodiments in the accompanying drawings.